Center connector for shoe assemblies of track laying vehicle

ABSTRACT

An endless track (52) for a track laying vehicle has a construction that facilitates replacement and repair of track components as well as providing an extended lifetime of use as compared to conventional vehicle tracks. The components of the track which facilitate its construction and maintenance include a track shoe (60), a replaceable road pad (62) for the track shoe (60), a pin assembly (64) for connecting laterally aligned pairs of the track shoes (60), a hollow pin (66) of the pin assembly (64), a center guide (68) that guides the track on the associated vehicle roadwheels, an end connector (72) that connects ends of the pins (66) associated with adjacent shoe assemblies (70), and a center connector (74) that cooperates with the end connectors (72) in connecting the shoe assemblies (70).

This is a divisional of co-pending application Ser. No. 752,186 filed onJuly 3, 1985 now U.S. Pat. No. 4,700,992.

TECHNICAL FIELD

This invention relates to an endless track and components thereof for atrack laying vehicle.

BACKGROUND ART

Endless tracks have been used for many years with vehicles such as tanksto facilitate off-the-road travel. A pair of such tracks areconventionally utilized with each vehicle at each of its lateral sides.An outwardly facing side of each track engages the ground while aninwardly facing side of the track engages an associated set ofroadwheels on the vehicle and a drive spocket, a compensating idlerwheel, and support rollers along an upper reach of the track above theroadwheels. The constantly increasing weight and speed of track layingvehicles has resulted in a decrease in the track life and a constantincreasing need for track maintenance by either repair or replacement.However, conventional endless tracks are not designed to facilitatetrack maintenance in the field as would most desirably be the case.

The conventional construction of an endless track for a track layingvehicle includes shoe assemblies which are connected along the length ofthe track with each shoe assembly including a pair of laterally spacedtrack shoes connected by an associated pair of pins. Each shoe assemblyconventionally has a metal shoe housing on which an outwardly facingroad pad and an inwardly facing roadwheel pad are mounted. Whileroadwheel pads do not normally wear significantly, road pads normally donot last more than 800 to 1000 miles. One particular problem is road padchunking that results from the heat produced with higher speeds andgreater weights of present day tanks. Prior attempts to improve trackdesigns have included stamped housing members such as shown by U.S. Pat.Nos. 1,313,266 Couch; 2,301,954 Knox; 2,327,909 Krotz; 2,353,124Burgess; and 2,548,626 Sinclair. However, the stamped housings disclosedby these prior references have not received any significant commercialacceptance.

To facilitate track maintenance, road pads of track shoes havepreviously been replaceable. Such replacement is usually achieved by useof a threaded connection that can loosen during use. Replaceable roadpads utilizing threaded connections are illustrated by U.S. Pat. Nos.2,332,976 Saurer et al; 3,357,750 Reynolds et al; and 4,262,972 Falk.U.S. Pat. No. 2,353,124 Burgess discloses a track shoe in which the roadpad is secured by rivets which would eliminate the loosening problempresent with threaded connections; however, such rivets make replacementof the road pad more difficult so that the replacement cannot beperformed as a field maintenance operation. Likewise, U.S. Pat. No.4,139,241 Huhne et al discloses a track shoe wherein deformation of theresilient pad allows insertion of retainer elements into claw-likeprojections; however, the assembly device utilized to perform the paddeformation also inhibits the replacement of the road pad as a fieldmaintenance operation.

Laterally aligned track shoes are conventionally connected by a pair ofpin assemblies that extend through the housings of the shoes. These pinassemblies conventionally each include an outer sleeve that includes apair of sleeve portions respectively located within the housings of thetwo shoes connected by the pin assembly. Each pin assembly also includesa pin that extends through both sleeve portions and rubber bushings thatare interposed between the pin and the sleeve portions by compressionupon insertion of the pin into the sleeve portions. Such compressionmust be sufficient so that there is no rotation between the bushing andthe outer sleeve portions or the pin upon bending of the track duringuse. However, such compression of the bushing results in a greaterresistance to the required bending during use and a consequent greaterpower requirement for driving of the associated vehicle. Conventionalpin assemblies incorporating compressed bushings are disclosed by U.S.Pat. Nos.: 1,973,214 Lamb; 2,089,210 Knox et al; 2,301,954 Knox;2,332,976 Saurer et al; 3,357,750 Reynolds et al; 4,139,241 Huhne et al;and 4,195,887 Ruddell.

Hollow pins have previously been utilized with vehicle tracks to reducethe track weight. See for example U.S. Pat. Nos. 1,863,858 Knox;1,973,214 Lamb; 3,762,778 Boggs et al; 3,948,574 Baller; 4,120,537 Roleyet al; 4,126,359 Holze; 4,163,589 Fox et al; 4,195,887 Ruddell;4,265,084 Livesay; 4,288,172 Livesay et al; 4,324,437 Narang; and4,395,074 Haldimann et al. However, such hollow pins reduce the strengthof the ends of the pins where end connectors are secured to provideconnection between adjacent shoe assemblies of the track and, as such,present a strength problem.

To provide guiding of vehicle tracks, each shoe assembly of conventionaltracks includes a center guide that projects in an inward direction tobe received within a center slot in the roadwheels. These center guidesare conventionally designed to clamp onto central portions of adjacentpins of adjacent shoe assemblies to cooperate with the pin endconnectors in securing the shoe assemblies to each other. The centerguides are conventionally clamped to the pins by threaded connectionsthat have the same loosening problem involved with conventionalreplaceable road pads as discussed above. Such prior center guides forvehicle tracks are disclosed by U.S. Pat. Nos. 2,089,210 Knox et al;2,283,936 Knox; 2,301,954 Knox; 2,332,976 Saurer et al; 3,357,750Reynolds et al; 3,467,446 Seelbach et al; 3,582,156 Korner et al;4,139,241 Huhne et al; and 4,262,972 Falk.

As mentioned above, adjacent shoe assemblies are conventionallyconnected by end connectors that extend between the adjacent pin ends.These ends connectors conventionally include a wedge connection that issecured by a threaded bolt and/or nut. Such threaded fastening of thewedge connector can loosen during use and requires a greater amount oftime for installation and removal than is desirable. Prior endconnectors for vehicle tracks are disclosed by U.S. Pat. Nos. 1,028,893Luther; 1,282,326 Turnbull; 1,446,870 Borst, Jr.; 1,913,098 Alden;2,957,731 Backhaus; 3,032,376 Blazek et al; 3,056,309 Horste; 3,467,446Seelbach et al; 4,175,798 Korner et al; and 4,262,973 Grilli et al.

Between the opposite pin ends, adjacent track shoes of vehicle tracksare conventionally connected by the clamping of the center guidesextending between intermediate portions of the adjacent pins asmentioned above at a location laterally between the shoes of the track.The dual function of guiding and connecting the adjacent pins results ina substantial loading during use. Usually, the center guide clamps ontoeach intermediate pin portion with two lines of contact that results in"reseating" due to the substantial loading involved during use. Suchreseating can ultimately produce wear that loosens the center connectionbetween the pins and the resultant useful lifetime of the track.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an improved vehicletrack and improved components thereof which have a modular constructionthat facilitates component replacement even in a field maintenancesituation to thereby provide an extended lifetime of effective use.

In carrying out the above object, a shoe for an endless track of a tracklaying vehicle is constructed in accordance with the present inventionto include a binocular-shaped housing including a pair of formed sheetmetal housing members with the same cross section as each other. Thisconstruction of the shoe housing permits both housing members to befabricated from the same formed sheet metal stock in an economicalmanner. The shoe housing also includes a pair of end plates thatcooperate in securing the pair of housings to each other. A roadwheelpad of resilient material is molded in situ on one side of the shoehousing to provide the engagement of the shoe with the roadwheels withan associated track laying vehicle with which the track is utilized. Theshoe also includes a replaceable road pad of resilient material and adetachable connection for securing the replaceable road pad to the shoehousing on the opposite side thereof as the roadwheel pad for engagementwith the ground during the vehicle travel while still permittingreplacement when the resilient material of the road pad becomes worn.

In the preferred construction of the track shoe, each shoe housingmember defines an elongated pin opening of a generally round crosssection extending between the pair of end plates, and each shoe housingmember also includes a pair of offset flanges that mate with the offsetflanges of the other member. A connection preferably provided by weldingsecures the flanges of the shoe housing members to each other at alocation between the associated elongated pin openings defined by theshoe housing members. These connected flanges of the shoe housingmembers define a web that extends between the elongated pin openings,and each shoe housing member includes a pin positioning groove locatedadjacent the web and facing toward its elongated pin opening. The web ofthe shoe housing preferably includes an opening through which theresilient material of the road pad extends between the opposite sides ofthe web in order to strengthen the bond between the resilient materialof the roadwheel pad and the shoe housing.

The preferred construction of the detachable connection for thereplaceable road pad of the track shoe includes at least one pin typeconnector, a hole in one of the end plates for receiving the pin typeconnector, and a retainer on the road pad. The pin type connector isinserted into the end plate hole to project outwardly therefrom andengage the retainer in order to secure the road pad to the shoe housing.The pin type connector is removable from the end plate to disengage theretainer in order to permit removal of the road pad for replacement.

In the most preferred construction of the detachable connection for thereplaceable road pad, the pin type connector of the connection has aspiral construction including a pointed end. The retainer on the roadpad includes a spring retainer portion that is elastically deformed bythe engagement thereof with the pointed end of the connector uponinsertion thereof through the end plate hole such that a spring forceretains the road pad on the track shoe. Preferably, the track shoe alsoincludes a second pin type connector, an associated hole in the otherend plate for receiving the second pin type connector, and a retainerincluding another spring retainer portion that is engaged by the secondpin type connector to secure the road pad to the housing.

The invention also involves the construction of the replaceable road padfor the track shoe of the endless track for use with a track layingvehicle. This replaceable road pad includes a sheet metal support formedto include a pair of pin troughs each of which has opposite ends and agenerally semicircular cross section that opens in the same direction asthe other pin trough. A web of the metal support extends between the twopin troughs thereof to cooperate therewith in defining one half of abinocular configuration. A resilient road pad is made of resilientmaterial molded in situ on the metal support on the opposite sidethereof as the direction toward which the pin troughs open. Between thetwo pin troughs, a retainer is mounted on the web of the metal supportand includes a pair of spring retainer portions which are respectivelylocated adjacent the opposite ends of the pin troughs. These springretainer portions are elastically deformed to provide the mounting ofthe replaceable road pad on the associated track shoe.

In its preferred construction, the replaceable road pad is formed as anelongated leaf spring having an intermediate portion located between theweb of the metal support and the resilient road pad. A connectionpreferably provided by rivets secures the intermediate portion of theleaf spring to the web of the metal support. Opposite ends of the leafspring extend from the secured intermediate portion thereof andconstitute the spring retainer portions of the retainer for securing thereplaceable road pad. Each leaf spring end includes a bent end portionthat defines a connector opening for use in securing the replaceableroad pad by associated connectors as previously described in connectionwith to the construction of the shoe of the endless track.

In the most preferred construction of the replaceable road pad, the webof the metal support includes end openings adjacent the ends of theretainer leaf spring to permit elastic deformation thereof upon mountingof the road pad on an associated track shoe. Strengthening ribs are alsoprovided on the metal support extending across the pin troughs at whichholes are also provided. The resilient material of the road pad extendsinto the metal support holes at the pin troughs to cooperate therewithin securing the resilient material of the resilient road pad againstmovement after the in situ molding on the metal support.

An endless track for use with a track laying vehicle and embodying theinvention is of the type including a plurality of shoe assemblies andconnectors that extend between the shoe assemblies. Each shoe assemblyincludes a pair of pin assemblies between which the connectors extend toconnect the adjacent shoe assemblies. Each pin assembly includes asleeve received within the associated shoe assembly. The sleeve includesa pair of sheet metal sleeve members formed to define a round openingthrough the sleeve. A metal pin is received within the opening in thesleeve and has opposite ends projecting outwardly from the sleeve topermit connection of adjacent shoe assemblies by connectors at theopposite ends of the pins of the shoe assemblies. A resilient bushing ismolded in situ between the sleeve and the pin and is bonded to both thesleeve and the pin.

The construction of the pin assembly with the resilient bushing moldedin situ between the sleeve and the pin permits the bushing to functionby deformation as adjacent shoe assemblies move with respect to eachother during vehicle travel. This deformation of the resilient bushingis achieved without the substantial compression necessary withconventional pin bushings of this type.

In the preferred construction of the pin assembly, the sleeve includes apositioning flange cooperatively defined by the sleeve members thereofand the resilient bushing material between the sleeve and the pin. Thispositioning flange is received within a positioning groove in theassociated shoe assembly to prevent rotation of the sleeve with respectto the shoe assembly while rotation of the pin with respect thereto ispermitted by the deformation of the resilient bushing as previouslydescribed.

The sleeve of the pin assembly preferably includes spaced portionshaving inner ends spaced from each other with the pin extendingtherebetween to provide a center connector location for the pinassembly. Outer ends of the spaced portions of the sleeve have theopposite ends of the pin projecting outwardly therefrom to provide endconnector locations. Each sleeve portion most preferably includes a pairof the sleeve members which have the same cross section as each other.Each sleeve member includes a main portion defining a generallysemicircular cross section and also includes a bent flange portionextending from the semicircular main portion. Cooperation of theassociated bent flange portions of each sleeve portion defines thepositioning flange thereof which is filled by the resilient bushingmaterial that is molded in situ between the sleeve and the pin. As ishereinafter more fully described, the pin of the pin assembly has ahollow intermediate portion received within the sleeve and also hasgenerally solid ends projecting outwardly from the sleeve to provide alightweight but high strength construction for connecting the adjacentshoe assemblies.

In accordance with the objectives of the invention, an endless track fora track laying vehicle is of the type including a plurality of shoeassemblies and end connectors that extend between the shoe assemblieswith each shoe assembly including a pair of pin assemblies that are of alightweight but high strength construction. Each shoe assembly includesan elongated pin that extends through the associated shoe assembly andhas a hollow intermediate portion for providing a lightweightconstruction. The hollow intermediate portion of the pin has oppositeends, and the pin includes a pair of opposite ends of a solidconstruction at the opposite ends of the hollow intermediate portion ofthe pin. These solid ends of the pin provide high strength locations forattachment of the end connectors that extend between the shoeassemblies.

In the preferred construction of the pin, the hollow intermediate pinportion and the solid pin ends have welded connections to each other.Spin welding is preferably utilized to secure the solid ends to thehollow intermediate portion of the pin, although other types of weldingand securement could also be used even though the spin welding is mostpreferred.

In the most preferred pin construction, each solid pin end has a flatsurface for orienting the pin with respect to an associated endconnector. Each solid pin end also preferably includes an end connectorattachment notch located diametrically opposite the flat surface thereoffor orienting the pin. Both the flat surface and the attachment notch ofeach solid pin end have inner curved portions for preventing stressconcentrations upon loading of the pin during use with end connectorsattached to the solid pin ends. A tapered end surface of each solid pinend is circumferentially aligned with the attachment notch thereof tofacilitate securement of an associated end connector of a constructionthat is hereinafter more fully described.

In carrying out the objectives of the invention, a center guide is alsoprovided for each shoe assembly of the endless track used for the tracklaying vehicle. Each shoe assembly with which the center guide isutilized includes a pair of shoes each of which has roadwheel and roadpads that face in opposite directions. Each shoe assembly with which thecenter guide is utilized also includes a pair of pin assemblies thatconnect the shoes and position the shoes in a laterally spacedrelationship with respect to each other.

The center guide constructed in accordance with the invention includes apair of guide members each of which has a mounting lug portion and acenter guide portion. A resilient material is bonded to both guidemembers with the lug portions and guide portions of each aligned withthose of the other to cooperatively provide a mounting lug and a centerguide projection. A connection of the center guide secures the mountinglug thereof between the laterally spaced shoes of the associated shoeassembly with the center guide projection extending from the shoeassembly in the direction toward which the roadwheel pads of the shoeface.

The construction of the center guide provides only a guiding function asopposed to conventional track designs wherein the center guide is partof a center connector that connects adjacent shoe assemblies. Isolatingthe center guide function from the center connector function reduces theloading on the center guide projection in order to provide a greaterlifetime of effective use.

In the preferred construction of the center guide, the center guideprojection includes an opening through both guide members and throughthe resilient material that bonds the guide members to each other. Themounting lug portions of the guide members are spaced farther from eachother than the guide portions, and each mounting lug portion includes aconnector hole for receiving a pin type connector of the connection forsecuring the center guide between the shoes of the associated shoeassembly. Each guide member also preferably includes a positioningflange located between its mounting lug portion and guide portion. Thepositioning flanges of the guide members are engageable with theadjacent shoes with the center guide mounted on the associated shoeassembly.

An endless track for use with a track laying vehicle and embodying theinvention includes a plurality of shoe assemblies as previouslymentioned with each shoe assembly including a pair of pins havingopposite ends projecting outwardly from the shoe assembly for connectionby end connectors that eliminate the problems associated withconventional wedge and threaded fastener type end connectors. Each endconnector includes a connector body having a pair of holes for receivingthe associated pair of pin ends. A spring retainer is mounted on theconnector body and resiliently engaged with the pin ends to secure theconnector body to the pin ends. With this resilient type of securement,there is no possibility of unthreading as is the case with conventionalend connectors.

In the preferred construction of the track end connector, each holeincludes a flat surface for orienting the associated pin end. Theconnector body of the end connector also preferably includes anintermediate opening into each hole with the retainer extending throughthe openings to secure the associated pin ends. The spring retainerpreferably comprises a unitary leaf spring having an intermediateportion secured to the connector body and opposite ends extending fromthe intermediate portion thereof through the openings into the holes.These opposite ends of the leaf spring extend into the attachmentnotches of the solid pin ends as previously described and thereby securethe pin ends within the end connector holes. Between its opposite ends,the intermediate portion of the leaf spring retainer preferably has arivet connection to the connector body to provide an uncomplicated yeteffective securement of the leaf spring retainer.

An endless track for use with a track laying vehicle and embodying theinvention includes a plurality of shoe assemblies each of which includesa pair of laterally spaced shoes and a pair of round pins extendingtherebetween, and a center connector is also provided for connecting theadjacent shoe assemblies by extending between the adjacent pins thereofat a location between the laterally spaced shoes. The center connectorhas a novel construction that prevents unseating during use of the trackas the shoe assemblies move with respect to each other.

The center connector of the invention includes a pair of clamp membershaving two pairs of opposed clamping surfaces. One clamping surface ofeach pair includes one location for engaging the associated pin withline contact that constitutes the sole engagement thereof with the pin.The other clamp surface of each pair includes two spaced locations forengaging the associated pin with two spaced line contacts thatconstitute the only engagement thereof with the pin. A connection of thecenter connector secures the clamp members thereof to each other witheach pair of clamping surfaces thereof engaging each pin at the threelocations of line contact which form a triangular shape. The threelocations of line contact insure secure clamping of each clampingsurface without the unseating problem of conventional center connectors.

Each clamp member of the center connector preferably includes a centralconnection hole and a pair of clamping flanges extending in oppositedirections from the central connection hole. One clamp member of thecenter connector has the clamping flanges thereof each provided with oneof the locations for engaging the associated pin with line contact,while the other clamp member has the clamping flanges thereof eachprovide with the other two locations for engaging the associated pinwith line contact.

In the preferred construction of the center connector, the connectionbetween the clamp members includes a threaded bolt that extends throughthe central hole of both clamp members between the pins connected by thecenter connector. The connection also includes a nut that is threadedonto the bolt thereof to secure the clamp members to each other witheach pair of clamping flanges engaging the associated pin at threespaced locations of line contact as previously described. The one clampmember that engages the associated pin with one location of line contactpreferably includes a longitudinal groove extending between its clampingflanges, and the bolt of the connection has a head that is receivedwithin the groove and has at least one flat surface positioned by thegroove to permit tightening of the nut for securing the clamp members toeach other.

As is evident from the above description, the track shoe, thereplaceable road pad, the pin assembly, the hollow construction of thepin with its solid ends, the center guide, the end connectors, and thecenter connector cooperate to provide a modular endless track for usewith a track laying vehicle in a manner that solves problems involvedwith conventional track designs.

The objects, features, and advantages of the present invention arereadily apparent from the following detailed description of the bestmode for carrying out the invention when taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a track laying vehicle including a pairof endless tracks embodying the present invention;

FIG. 2 is a partial exploded perspective view of one of the vehicletracks embodying the invention;

FIG. 3 is a side view of the track taken along the direction of line3--3 in FIG. 2;

FIG. 4 is a cross sectional view taken through the track along thedirection of line 4--4 in FIG. 3;

FIG. 5 is a partial sectional view taken along the directional of line5--5 of FIG. 4 with the track illustrated as shoe assemblies thereofmove with respect to each other during vehicle travel;

FIG. 6 is an exploded perspective view of a binocular-shaped housing ofa track shoe of the track;

FIG. 7 is a perspective view of the binocular-shaped shoe housing in itsassembled condition;

FIG. 8 is a perspective view of a formed sheet metal support of areplaceable road pad for the track shoe;

FIG. 9 is a perspective view of the replaceable pad after resilientmaterial has been molded in situ on the metal support;

FIG. 10 is a sectional view through the replaceable road pad taken alongthe direction of line 10--10 in FIG. 9;

FIG. 11 is a plan view of the replaceable road pad taken along thedirection of line 11--11 in FIG. 10;

FIG. 12 is an end view of the replaceable road pad taken along thedirection of line 12--12 in FIG. 11;

FIG. 13 is a partial sectional view through the replaceable road padtaken along the direction of line 13--13 in FIG. 11;

FIG. 14 is a view of the track shoe taken in the same direction as theleft shoe illustrated in FIG. 4 with the roadwheel pad bonded theretobut without the replaceable road pad assembled to the shoe;

FIG. 15 is an end view of the track shoe taken along the direction ofline 15--15 in FIG. 14;

FIG. 16 is a sectional view taken through the track shoe along thedirection of line 16--16 in FIG. 14;

FIG. 17 is a view of the track shoe taken along the direction of line17--17 in FIG. 14;

FIG. 18 is a view illustrating the track shoe just prior to assembly ofthe replaceable road pad to the shoe housing;

FIG. 19 is a view of the track shoe after the replaceable road pad hasbeen assembled to the shoe housing;

FIG. 20 is a view of the track shoe prior to assembly of the replaceableroad pad but flipped upside down from the position of FIG. 18;

FIG. 21 is an exploded perspective view of the sleeve and pin of a pinassembly of the endless track;

FIG. 22 is a view of the pin assembly after molding of an elastomericbushing in situ between the sleeve and the pin of the assembly;

FIG. 23 is a partially broken away view of the pin of the pin assembly;

FIG. 24 is an exploded perspective view of a center connector of theendless track;

FIG. 25 is a side view taken in section through the center connector andadjacent pins of adjacent shoe assemblies of the track to illustrate themanner in which the center connector connects the shoe assemblies;

FIG. 26 is an exploded perspective view of an end connector of theendless track;

FIG. 27 is a sectional view taken through the end connector generallyalong the direction of line 27--27 in FIG. 26 with the end connectorconnecting adjacent pin ends of adjacent shoe assemblies;

FIG. 28 is a plan view of the end connector taken along the direction ofline 28--28 of FIG. 27;

FIG. 29 is a sectional view taken along the direction of line 29--29 inFIG. 26 through the end connector and one of the pin ends connectedthereby to illustrate the manner in which the end connector is securedto the pin end;

FIG. 30 is an end view of the track shoe taken partially in sectionthrough the associated pin ends along the direction of line 30--30 inFIG. 4;

FIG. 31 is a sectional view through the track shoe taken along thedirection of line 31--31 of FIG. 30;

FIG. 32 is a sectional view taken along line 32--32 of FIG. 31 through aspiral pin connector of the type utilized to secure the replaceable roadpad to the track shoe; and

FIG. 33 is a partial sectional view taken through an end plate of thehousing along the direction of line 33--33 of the FIG. 31 to illustratethe manner in which the track shoe is secured against axial movementalong the pin assembly.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to FIG. 1 of the drawings, a track laying vehicleembodied by a tank 50 includes a pair of endless tracks 52 each of whichembodies the invention and each of which includes improved componentsembodying the invention as is hereinafter more fully described. Eachendless track 52 is supported for movement below an associated set ofroadwheels 54 as well as around a compensating idler wheel 56 and adrive sprocket 58. During operation, the endless tracks 52 are pulledrearwardly under roadwheels 54 by drive sprocket 58 and the unshownupper portion of the track moves forwardly around the idler wheel 56which is compensated to maintain the track at a predetermined tension.

With reference to FIG. 2, the construction of the endless track 52 willbe briefly described to facilitate an understanding of each componentthereof prior to a detailed description of the components for a completeunderstanding of the invention. Along the length of the track 52, tworows of shoes 60 are arranged in a side-by-side relationship andfunction to support the roadwheels 54 for movement over the ground onwhich the tank is travelling. Each shoe 60 includes a replaceable roadpad 62 illustrated in FIG. 2 for engaging the ground during the vehicletravel. A pair of pin assemblies 64 extend between each aligned pair oftrack shoes 60 to permit movement of the shoes with respect to eachother as the track 52 moves around the roadwheels 54, idler wheel 56,and the drive sprocket 58. Each pin assembly 64 includes a hollow pin 66of a construction that makes the track 52 lightweight withoutsacrificing strength of the pins at required locations. Between eachlaterally aligned pair of track shoes 60, a center guide 68 is providedto guide the track along the associated roadwheels, idler wheel, anddrive sprocket. Shoe assemblies 70 are provided by the laterally alignedpairs of shoes 60, the associated pair of pin assemblies 64, and thecenter guide 68 located between each pair of laterally aligned shoes 60.End connectors 72 connect the adjacent ends of hollow pins 66 associatedwith adjacent shoe assemblies 70 as is hereinafter more fully described.In addition, each adjacent pair of shoe assemblies 70 are connected byan associated center connector 74 (FIG. 5) extending betweenintermediate portions of the adjacent pins 66 as is also hereinaftermore fully described.

As illustrated in FIG. 3, the track shoes 60 of adjacent shoe assemblies70 are positioned relatively close to each other and are interposed asillustrated in FIG. 4 between the ground G and the roadwheels 54 duringdriving of the associated tank. As illustrated in FIGS. 6 and 7, eachtrack shoe includes a binocular-shaped shoe housing 76 having a pair offormed sheet metal housing members 78 with the same cross section aseach other. The shoe housing 76 also includes a pair of end plates 80that cooperate in securing the pair of housing members 78 to each otherin a manner which is hereinafter more fully described. As bestillustrated in FIGS. 14 through 17 and 20, the track shoe also includesa roadwheel pad 81 made of resilient material 82 (FIGS. 16 and 17) thatis molded in situ on one side of the shoe housing 76. The replaceableroad pad 62 of the track shoe is illustrated in FIGS. 9 through 13, 18,and 19, and includes a resilient road pad 84 molded from resilientmaterial 86 (FIG. 10) for engaging the ground during vehicle travel.First and second pin type connectors 88 and 90 of the track shoe arebest illustrated in FIG. 31 and cooperate to provide a detachableconnection that secures the replaceable road pad 62 to the shoe housing76 in a manner which is hereinafter more fully described.

With reference to FIGS. 6, 7, and 15, the construction of each shoehousing member 78 preferably defines an elongated pin opening 92 of agenerally round cross section extending between the end plates 80 withthe ends of the housing members received within complementary associatedopenings 94 (FIG. 6) in the end plates 80 and secure thereto asillustrated in FIG. 7 by a suitable brazing operation. Each shoe housingmember 78 includes a pair of offset flanges 96 and 98 with the oneflange 96 shorter than the other flange 98 at each of its ends. Theidentical cross sections of the housing members 78 are oriented inoppositely facing directions with respect to each other such that theoffset flanges 96 and 98 mate with each other as best illustrated inFIG. 17. A connection preferably provided by welds 100 secures thelonger flanges 98 to each other to provide securement of the housingmembers 78 to each other.

As illustrated in FIG. 7, the flanges 96 and 98 of the shoe housingmember 78 define a web 102 that extends between the elongated pinopenings 92 laterally intermediate the end plates 80. Each shoe housingmember 78 as best illustrated in FIG. 15 also includes a pin positioninggroove 104 located adjacent the web 102 and facing toward the associatedelongated pin opening 92. Each end plate opening 94 also includes acomplementary groove portion 106 that receives the housing memberportion defining the associated pin groove 104. As is hereinafter morefully described, the pin grooves 104 are utilized to prevent rotation ofthe pin assemblies 64 previously mentioned in connection with FIG. 2.Between the pin grooves 104, the web 102 of the housing members 78defines an opening 108 that has an elongated rectangular shape asillustrated in FIG. 7. The roadwheel pad 81 as previously mentioned ismolded in situ to the assembled shoe housing 76 with the resilientmaterial 82 thereof extending through the web opening 108 as illustratedin FIG. 16 between the opposite sides of the web 102 in order to enhancethe securement of the roadwheel pad to the housing members 78. Asuitable adhesive is also preferably applied to the housing members 78prior to the in situ molding of the roadwheel pad 81 in order to furtherenhance the securement of the material 82 to the shoe housing.

As best illustrated in FIGS. 4 and 6, the shoe housing end plates 80each have a pair of lugs 109 that cooperate to define a groove 109a.Opposite ends of the housing member web 102 are received within the luggrooves 109a as best shown in FIGS. 4 and 7 to cooperate with thesecurement provided by the brazing operation in locating the housingmembers 78 and the end plates 80 with respect to each other.

As previously mentioned in connection with FIG. 31, the replaceable roadpad 62 is detachably secured to the track shoe housing 76 by the firstand second pin connectors 88 and 90 which are received within associatedholes 110 and 112 of the pair of end plates 80. As is hereinafter morefully described, a retainer 114 of the replaceable road pad 62 hasspring retainer portions 116 and 118 which are respectively engaged byends of the pins 88 and 90 that project outwardly from the associatedend plates 80. The first pin type connector 88 is removable from theassociated end plate opening 110 by a punching operation, which caneasily be performed with a hammer and a punch, and is thereby movedtoward the right in the void region 120 defined by the road pad material86. The spring retainer portion 116 is then free so that the left sideof the replaceable road pad 62 can be pivoted downwardly about the rightpin connector 90 so as to clear the lower side of the left end plate 80and permit movement of the replaceable road pad toward the left so thatthe spring retainer portion 118 disengages the pin connector 90 suchthat the road pad is then free for replacement.

A new road pad 62 is replaced on the shoe 60 by first inserting thespring retainer portion 118 into engagement with the pin connector 90and then pivoting the road pad clockwise thereabout into the generalposition illustrated in FIG. 31. Pin connector 88 which was previouslyremoved as described above is then inserted into the left end of theassociated end plate hole 110 and driven to the position shown intoengagement with the spring retainer portion 116. During the initialpositioning, the spring retainer portion 118 is elastically deformed andthe spring retainer portion 116 is subsequently deformed as the pin 88is driven into the secured position. To facilitate the replacement, thepin 88 has a pointed end 88a that initially engages the spring retainerportion 116. As illustrated by the pin connector 88 illustrated in FIG.32, both of the pin connectors 88 and 90 have a spiral cross sectionthat insures secure positioning thereof within the associated end platehole despite manufacturing tolerances while still permitting reuse ofthe pin connectors after removal from the end plates.

With reference to FIGS. 8 and 9, the replaceable road pad 62 includes asheet metal support 124 that is formed by a stamping operation to have apair of pin troughs 126. Each pin trough 126 has opposite ends 128 and130 and a generally semicircular cross section that opens in the samedirection as the other pin trough as illustrated in FIG. 12. The stampedsheet metal support 124 also includes a web 132 extending between thepin troughs 126 as illustrated in FIGS. 8 and 9 to cooperate therewithin defining one half of a binocular configuration. The resilientmaterial 86 of the road pad 84 is molded in situ on the formed metalsupport 124 on the opposite side thereof as the direction toward whichthe pin troughs 126 open. A suitable adhesive is preferably applied tothe formed metal support 124 to facilitate the securement between theroad pad material 86 and the support after the in situ molding.

As best illustrated by combined reference to FIGS. 8 through 11, thespring retainer 114 previously described is mounted on the web 132 ofthe formed metal support 124 between the two pin troughs 126 and has thepair of spring retainer portions 116 and 118 thereof respectivelylocated adjacent the opposite ends 128 and 130 of the pin troughs. Aspreviously mentioned, these spring retainer portions 116 and 118 areelastically deformed during the mounting of the replaceable road pad 62on the associated track shoe as previously described.

As best illustrated in FIGS. 10 and 11, the preferred construction ofthe retainer 114 is embodied by an elongated leaf spring having anintermediate portion 134 located between the web 132 of the metalsupport 124 and the resilient road pad 84 provided by the resilientmaterial 86 that is bonded in situ on the support. A pair of rivets 136provide a connection that secures the intermediate portion 134 of theleaf spring retainer 114 to the support web 132 with the opposite endsof the leaf spring providing the spring retainer portions 116 and 118.Upon assembly of the replaceable road pad 62 to the shoe housing 76, theheads of rivets 136 are received within molded depressions 138 of theroadwheel pad material 82 as illustrated in FIGS. 16 and 18.

As illustrated in FIGS. 10 and 11, the spring retainer portions 116 and118 that constitute the ends of the leaf spring retainer 114 haverespective bent end portions 140 and 142 that define associatedconnector openings 144 and 146 of semicircular shapes for respectivelyreceiving the pin connectors 88 and 90 previously described inconnection with FIG. 31. As illustrated in FIGS. 10 and 11, openings 148and 150 are provided in the web 132 adjacent the ends of the leaf springretainer 114 to permit elastic deformation of the spring retainerportions 116 and 118 during the mounting of the replaceable road pad 62as previously described.

As best illustrated in FIGS. 8, 9, and 11 through 13, the formed sheetmetal support 124 of the replaceable road pad includes strengtheningribs 152 extending across the pin troughs 126. Three of the ribs 152 areprovided on each trough 126 as illustrated, with two of the ribs locatedrespectively adjacent the ends of the trough and with a third riblocated centrally between the ends of the trough. Also, each trough isprovided with holes 154 at the pin troughs with two holes preferablyprovided on each trough such that there is one hole between each pair ofthe strengthening ribs 152. As illustrated in FIG. 13, the resilientmaterial 86 of the resilient road pad 84 extends into the holes 154 ofthe metal support 124 at the pin troughs to cooperate therewith insecuring the resilient material after the situ molding thereof on thesupport.

The replaceable road pad 62 described above and illustrated in FIG. 18is thus secured to the track shoe 60 by positioning thereof between theend plates 80 for securement by the pin connectors 88 and 90 aspreviously described and illustrated in FIG. 19. Prior to the securementof the replaceable road pad 62, the track shoe 60 on the opposite sideillustrated in FIG. 18 has the construction illustrated in FIG. 20 wherethe roadwheel pad 81 is molded in situ to the shoe housing in the mannerpreviously described.

As previously described in connection with FIG. 2, each shoe assembly 70includes a pair of the laterally aligned track shoes 60 of theconstruction defined above and a pair of the pin assemblies 64 thatconnect the pair of track shoes. The construction of each pin assembly64 as illustrated in FIG. 22 includes a sleeve 156 that is receivedwithin the track shoes of the associated shoe assembly as is hereinaftermore fully described. Sleeve 156 includes a pair of sheet metal sleevemembers 158 that are formed to define a round opening 160 (FIG. 30)through the sleeve. The pin 66 of the assembly 64 is received within theopening of the sleeve 156 as illustrated in FIG. 22 and has oppositeends 162 projecting outwardly from the sleeve 156 to permit connectionof adjacent shoe assemblies by connectors at the opposite ends of thepins thereof as is hereinafter more fully described. With the pin 66positioned within the sleeve 156, a resilient bushing 164 bestillustrated in FIG. 30 is molded from a suitable elastomeric material insitu between the sleeve and the pin and is bonded to both the sleeve andthe pin such that relative rotation therebetween along the length of thepin assembly is controlled by elastic deformation of the resilientbushing. In order to assist in securing the bonding of the bushing 164,it is preferable to first apply a suitable adhesive to the pin 66 and tothe inner side of the sleeve 156 prior to the in situ molding of thebushing.

As best illustrated in FIG. 30, each pin assembly 64 is compressed andthen inserted through the housing openings 92 of the associated pair oftrack shoes 60. Diametrically opposite gaps 166 between the sleevemembers 158 are provided to permit the compression that allows theinsertion of the pin assembly 64 into the track shoe 60. It should benoted that the amount of compression necessary is relatively small, onlyon the order of about 5% of so, as compared to the compression necessarywith conventional bushings for pin assemblies of conventional trackswherein the bushings are made as separate components as opposed to thein situ bushing molding herein described. As such, it is much easier toinsert the pin assemblies 64 into the track shoes 60 in order to permitreplacement or repair of any shoe assembly as may be necessary.

With continuing reference to FIG. 30, each pin and bushing assembly 64includes a positioning flange 168 received within the associated trackshoe housing groove 104 in order to prevent rotation thereof withrespect to the track shoe. The positioning flange 168 is cooperativelydefined by formed flanges 170 of the sleeve members 158 and by aprojecting lug 172 of the bushing 164 with this lug positioned betweenthe sleeve member flanges 170. Ends of the sleeve member flanges 170 arespaced from each other by the adjacent gap 166 previously described soas to permit compression of the bushing lug 172 and the rest of thebushing 164 as previously described during the insertion of the pinassembly 64 into the track shoe.

As best illustrated in FIG. 22, the sleeve 156 of the pin assembly 64includes spaced sleeve portions 156a with the pin 66 extendingtherebetween to provide a center connector location 174 for the pinassembly as is hereinafter more fully described. The spaced portions156a of the sleeve also have outer ends from which the opposite ends 162of the pin 66 project outwardly to provide end connector locations 176as is hereinafter more fully described. Each sleeve portion 156aincludes a pair of the sleeve members 158 as previously described andbest illustrated in FIG. 30. Each of the sleeve members 158 includes amain portion 178 of a generally semicircular cross section and alsoincludes the bent flange portion 170 previously described forcooperating with the bushing lug 172 to provide the positioning flange168.

With reference to FIG. 33, the inboard end plate 80 of each track shoe60 is provided with an Omega-shaped clip 180 associated with each pinassembly 64 to maintain the pin assembly within the track shoe. Asuitable milling cutter or other operation is used to provide a pair ofslots 182 through each shoe housing member 78 and partially into theinboard end plate as illustrated. After insertion of the pin assembly 64into the track shoe 60, the slots 182 are positioned inboard from theinner ends of the sleeve members 158 of the pin assembly. The clips 180have suitable tool holes 183 that are used to force the legs 184 of theclip toward each other in order to permit its assembly as illustratedwith a positioning lug 186 thereof aligned with the sleeve flanges 170.The assembled clips 180 thus engage the inner ends of the sleeve members158 to prevent the pin assemblies 64 from being withdrawn from the trackshoes. As is also obvious from FIG. 33, the pin 66 of the pin assembly64 has a hollow intermediate portion 188 received within the sleeve 156as well as including the solid ends 162 illustrated in FIG. 23 as ishereinafter more fully described.

With reference to FIG. 23, the pin assembly of each shoe assemblyincludes the elongated pin 66 which extends through the associated shoeassembly as previously described and has the hollow intermediate portion188 whose round cross section was previously described in connectionwith FIG. 33. This hollow intermediate portion 188 of the pin 66provides a lightweight construction which substantially reduces theweight of the endless track in view of the large number of pins used oneach tank vehicle with which two of the endless tracks are used. Thehollow intermediate portion 188 of the pin has opposite ends 190 betweenwhich a uniform cross section is preferably provided. Pin 66 alsoincludes the pair of opposite ends 162 previously mentioned inconnection with the description of the pin assembly 64. These pin ends162 extend from the ends 190 of the intermediate pin portion 188 andhave a solid construction to provide high strength locations forattachment of the end connectors that extend between the shoe assembliesas is hereinafter more fully described.

With continuing reference to FIG. 23, the opposite ends 190 of thehollow intermediate pin portion 188 preferably have welded connections192 to the solid pin ends 162. These welded connections 192 are mostpreferably made by a spin welding operation. It will be noted that eachsolid end 162 of the pin 66 has a round hole 194 aligned with a centralhole 196 through the hollow intermediate portion 188 of the pin. Thesepin end holes 194 facilitate alignment during the spin welding operationthat provides the welded connections 192.

As illustrated by combined reference to FIGS. 23, 27, and 29, each solidpin end 162 has a flat surface 198 for orienting the pin with respect toan associated end connector as is hereinafter more fully described. Inaddition, each solid pin end 162 also includes an end connectorattachment notch 200 located diametrically opposite the flat surface 198thereof that is utilized to orient the pin. The flat surface 198 of thepin end has a curved inner portion 202 while the attachment notch 200has a curved inner portion 204. These curved inner portions 200 and 204prevent stress concentrations upon loading of the pin during use. Also,each solid pin end 162 has a tapered end surface 206 circumferentiallyaligned with the attachment notch 200 to facilitate mounting of anassociated end connector as is hereinafter more fully described. It willbe noted that each solid pin end 162 is shown with an end hole 208 whichis used in supporting the pin during its fabrication. While the endholes 208 render the pin ends 162 less than completely solid, the crosssections of the pin ends are completely solid inwardly from where theassociated end connectors are mounted just outward from the outer endsof the holes 194. The solid locations are where the stresses of the pinends are primarily carried and thereby provide a high strengthconstruction despite the hollow construction of the intermediate portion188 for weight reduction.

With reference to FIGS. 3 and 4, the center guide 68 of each shoeassembly 70 is located between the pair of shoes 60 thereof whoseroadwheel pads 81 and road pads 84 face in opposite directions and areconnected by the associated pair of pin assemblies as previouslydescribed. It should be noted that the center guide 68 of each shoesassembly 70 does not perform any connecting function between theadjacent shoe assemblies and the loading thereof is thus not subjectedto any additional forces other than that necessary to provide theguiding function of the track on the associated vehicle.

As illustrated in FIG. 4, the center guide 68 includes a pair of guidemembers 210 each of which has a mounting lug portion 212 and a centerguide portion 214. A resilient material 216 is bonded to both guidemembers 210, preferably by an in situ molding operation wherein asuitable adhesive is first applied to each guide member to enhance thebonding. The lug portions 212 and guide portions 214 of each guidemember 210 are aligned with those of the other after the in situ moldingto cooperatively provide a mounting lug 218 and a center guideprojection 220. A connection provided by pin type connectors 222 securesthe mounting lug 218 between the laterally spaced shoes 60 of theassociated shoe assembly 70, in a manner which is hereinafter more fullydescribed, with the center guide projection 220 extending from the shoeassembly in the direction toward which the roadwheel pads 81 of the shoeassembly face. The projection 220 is received between laterally spacedguide plates 223 of the roadwheels 54 to provide the guiding functionthat maintains the track in position with respect to the roadwheelsduring vehicle travel.

As illustrated in FIGS. 1, 4, and 5, the center guide 68 has its centerguide projection 214 provided with an opening 224 through both guideportions 214 and through the resilient material 216 that bonds the guidemembers 210 to each other. Below the opening 224 as viewed in FIG. 4,the mounting lug portions 212 of the guide members 210 are spacedfarther from each other than the guide portions 214 to provide anadditional amount of resilient material 216 at this location and aresultant increased extent of compressibility that facilitates removalof the center guide as described below. Each mounting lug portion 212includes a connector hole 226 for receiving the associated pin connector222. The pair of pin connectors 222 preferably have the spiralconfiguration previously described in connection with FIG. 31 andcooperate to secure the center guide 68 between the shoes 60 of theassociated shoe assembly 70.

As illustrated in FIGS. 30 and 31, the inboard end plate 80 of eachtrack shoe 60 includes a vertical slot 228 into which the associated pinconnector 222 projects from a mounting hole 230 in the end plate. Eachguide member 210 as illustrated in FIG. 5 has its mounting lug providedwith a mounting flange 232 that is received within the associated endplate slot 228 with the pin connector 222 thereof securing the centerguide in position in cooperation with the other pin connector on theother side of the center guide. At the lower end of the center guide 68,the mounting flanges 232 are provided with tapered surfaces 234 thatconverge in a downward direction. A suitable tool with tapered surfacesfor engaging the tapered flange surfaces 234 is utilized to force themounting lug portions 212 toward each other in order to remove thecenter guide 68 when replacement or repair is necessary. Such movementof the mounting lug portions 212 toward each other releases the centerguide 68 from the shoe assembly when the mounting flanges 232 clear theinner ends of the pin connectors 222. Likewise, the tapered surfaces 234engage the ends of the pin connectors 222 upon mounting and force themounting lug portions 212 toward each other in order to permit downwardmovement of the center guide until the pin connectors 222 move into theassociated holes 226 for securement. Each guide member 210 is providedwith a positioning flange 236 located between its guide portion 210 andmounting lug portion 212 and engageable with the upper edge of theadjacent shoe end plate 80 to properly position the center guide in themounted relationship.

With reference to FIG. 2, the endless track 52 for the track layingvehicle includes a plurality of shoe assemblies of the construction aspreviously described with each shoe assembly including the pair of pins66 whose ends 162 project outwardly from opposite lateral sides of theshoe assembly. End connectors 72 connect the adjacent pin ends 162 ofadjacent shoe assemblies 70 in a manner more specifically describedbelow.

With reference to FIGS. 26 through 29, the construction of the endconnector 72 includes a connector body 238 having a pair of holes 240for receiving the associated pair of pin ends 162. A spring retainer 242is mounted on the connector body 240 and resiliently engaged with thepin ends 162 to secure the connector body to the pin ends and therebyprovide interconnection of the adjacent shoe assemblies with which thesepin ends are associated. Provision of the spring retainer 242 forsecuring the pin ends with the connector body 238 in the mannerdescribed eliminates the necessity for a conventional wedge connectorwith an associated threaded connection that can be loosened aspreviously described. Furthermore, as is hereinafter obvious from thefollowing discussion of the specific construction of the end connector72, removal and installation of the end connector is much easier andfaster so as to facilitate field maintenance and repair in the samemanner involved with all of the other components of the endless track.

As best illustrated in FIG. 26, each hole 240 includes a flat surface244 for orienting the associated pin end 162 by engaging its flatsurface 198 as illustrated in FIG. 27. Other than the flat surface 244,the rest of each hole 240 has a round shape which is concentric with thecentral axis of the associated pin end 162. An elongated grove 246 ofthe connector body is illustrated in FIGS. 27 and 28 and defines anintermediate opening 248 into each hole 240 with retainer 242 extendingthrough the openings to secure the associated pin ends 162. The groove246 also includes a retainer seat 250 on which the spring retainer 242is mounted as described below.

As illustrated in FIGS. 26, 27, and 28, the spring retainer 242comprises a unitary leaf spring 252 that is received within theconnector body groove 246 so as not to be exposed during use. Retainerleaf spring 252 includes an intermediate portion 254 that is secured inengagement with the retainer seat 250 by a connection preferablyembodied by a rivet 256 as best illustrated in FIG. 27. Opposite ends258 of the retainer leaf spring 252 extend from the intermediate portion254 thereof through the associated pair of intermediate openings 248into the holes 240 for engagement with the associated pin ends 162. Eachretainer spring end 258 engages the associated pin end 162 within thenotch 200 in the assembled position so as to thereby retain the endconnector 72 on the pin end. Each retainer spring end 258 preferably hasits extreme end portion 260 formed in a hook shape as best illustratedin FIG. 27 so that it can be grasped with a suitable tool and deflectedto permit removal of the end connector 72 from the associated pair ofpin ends 162. Upon assembly, the end connector 72 is moved over theassociated pair of pin ends 162 and the opposite ends 258 thereof engagethe tapered end pin surfaces 206 (FIG. 29) of the pins so as to beelastically deflected prior to movement into the associated notches 200as illustrated.

As is evident from the above description of the end connector 72, theconstruction involved facilitates assembly of the end connector as wellas facilitating disassembly so that field maintenance and repair can beperformed. In addition, the construction of the end connector 72provides an effective interconnection between adjacent shoe assemblies70 by engaging the adjacent pin ends thereof without requiring anyconventional wedge type connector and an associated threaded connectorthat can become loosened during use.

With reference to FIG. 2, the endless track 52 for the track laying tanktype vehicle described includes a plurality of the shoe assemblies 70 aspreviously described with each including a pair of laterally spacedshoes 60 and a pair of round pins 66 extending between the shoes withthe center connectors 74 connecting adjacent shoe assemblies byextending between adjacent pins thereof at a location between thelaterally spaced pairs of shoes. As previously mentioned in connectionwith the description of the center guide 68, the guiding functionprovided by the center guide and the connecting function provided by thecenter connector 74 are separate so that the loading for each functiondoes not provide loading of the component providing the other function.Such separation of the loading for the guiding and center connectingfunctions provides the resultant endless track 52 with greater abilityto withstand loading and hence a more extended lifetime than trackswhere the center guide and center connector are combined as onecomponent.

With reference to FIGS. 3, 24, and 25, the center connector 74 includesa pair of clamp members 262 and 264 which include two pairs of clampingsurfaces 266 and 268. One clamping surface 266 of each pair of clampingsurfaces includes one location 270 for engaging the associated pin 66 atits center connector location 174 (FIG. 22) with line contact thatconstitutes the sole engagement thereof with the pin. The other clampingsurface 268 of each pair includes two spaced locations 272 and 274 ofline contact for providing the only engagement thereof with the centerconnector location 174 (FIG. 22) of the associated pin 66. A connectiongenerally indicated by 276 secures the clamp members 262 and 264 to eachother with each pair of clamping surfaces 266 and 268 thereof engagingeach pin center connector location 174 (FIG. 22) at the three locationsof line contact which form a triangular shape with each other as bestillustrated in FIGS. 5 and 25. By engaging the pins with three locationsof line contact in the triangular shape disclosed, there is no unseatingproblem as is the case with conventional center connectors where thereis surface-to-surface contact or four or more locations of engagement.With these conventional center connectors, tolerances result in aconnector that cannot maintain a seated relationship with the pinsduring an extended lifetime of use.

As best illustrated in FIG. 24, clamp member 262 includes anintermediate portion 278 having a central connection hole 280 and alsoincludes a pair of clamping flanges 282 extending in opposite directionsfrom the connection hole with the one clamping location 270 provided oneach of these clamping flanges. The other clamp member 266 includes anintermediate portion 284 having a central connection hole 286 and alsoincludes a pair of clamping flanges 288 extending in opposite directionsfrom its connection hole with the two clamping locations 272 and 274provided on each of these clamping flanges.

As illustrated in both FIGS. 24 and 25, the connection 276 preferablyincludes a threaded bolt 290 that extends through the central connectionholes 280 and 286 of both clamp members 262 and 264 at a locationbetween the two pins 66 connected by the center connector 74. A nut 292of the connection 276 is threaded onto the bolt 290 to secure the clampmembers 262 and 264 to each other with each pair of clamping flanges 282and 288 engaging the associated pin 66 at three spaced locations 270,272, and 274 of line contact as previously described. The one clampmember 262 opposite the nut 292 includes a longitudinal groove 294extending between the clamping flanges 282 thereof and having a pair ofside surfaces 296 that face toward each other. The bolt 290 of theconnection has a head 298 that is received within the groove 294 and hasa pair of flat surfaces 300 engaged with the side surfaces 296 of thegroove 294 in the one clamp member 262 in order to permit tightening ofthe nut 292 without any tool positioning the bolt.

While the best mode for carrying out the invention has been described indetail, those familiar with the art to which this invention relates willrecognize various alternative ways of practicing the invention asdefined by the following claims.

What is claimed is:
 1. In an endless track for a track laying vehicle,said endless track being of the type including a plurality of shoeassemblies each of which includes a pair of laterally spaced shoes and apair of round pins extending therebetween, a center connector forconnecting adjacent shoe assemblies by extending between adjacent pinsthereof at a location between the laterally spaced shoes, said centerconnector comprising: a pair of clamp members including two pairs ofopposed clamping surfaces; one clamping surface of each pair includingone location for engaging the associated pin with line contact thatconstitutes the sole engagement thereof with the pin; the other clampingsurface of each pair including two spaced locations for engaging theassociated pin with two spaced line contacts that constitute the onlyengagement thereof with the pin; a connection for securing the clampmembers to each other with each pair of clamping surfaces thereofengaging each pin at the three locations of line contact which form atriangular shape; each clamp member including a central connection holeand a pair of clamping flanges extending in opposite directions from thecentral connection hole; one pair of clamping flanges each beingprovided with one of the locations for engaging the associated pin withline contact; the other pair of clamping flanges each being providedwith the other two locations for engaging the associated pin with linecontact; the connection including a threaded bolt that extends throughthe central connection holes of both clamp members between the pinsconnected thereby; the connection also including a nut that is threadedonto the bolt thereof to secure the clamp members to each other witheach pair of clamping flanges engaging the associated pin at threespaced locations of line contact; one clamp member including alongitudinal groove extending between the clamping flanges thereof andhaving at least one side surface; and the bolt of the connection havinga head that is received within the groove and has at least one flatsurface positioned by said one side surface of the longitudinal grooveto permit tightening of the nut for securing the clamp members to eachother.
 2. A track center connector as in claim 1 wherein said one clampmember having the longitudinal groove that positions the bolt head alsoincludes the pair of clamping flanges which each have one location forengaging the associated pin with line contact, and the other clampmember being engaged by the nut and including the pair of clampingflanges which each have two locations for engaging the associated pinwith line contact.
 3. A track center connector as in claim 2 wherein thelongitudinal groove in said one clamp member has a pair of sidesurfaces, and the bolt of the connection having its head provided with apair of flat surfaces each of which is positioned by one of the sidesurfaces of the longitudinal groove.
 4. In an endless track for a tracklaying vehicle, said endless track being of the type including aplurality of shoe assemblies each of which includes a pair of laterallyspaced shoes and a pair of round pins extending therebetween, a centerconnector for connecting adjacent shoe assemblies by extending betweenadjacent pins thereof at a location between the laterally spaced shoes,said center connector comprising: a pair of clamp members including twopairs of opposed clamping surfaces; one clamping surface of each pairincluding one location for engaging the associated pin with line contactthat constitutes the sole engagement thereof with the pin; the otherclamping surface of each pair including two spaced locations forengaging the associated pin with two spaced line contacts thatconstitute the only engagement thereof with the pin; a connection forsecuring the clamp members to each other with each pair of clampingsurfaces thereof engaging each pin at the three locations of linecontact which form a triangular shape; each clamp member including acentral connection hole and a pair of clamping flanges extending inopposite directions from the central connection hole; one pair ofclamping flanges each being provided with one of the locations forengaging the associated pin with line contact; the other pair ofclamping flanges each being provided with the other two locations forengaging the associated pin with line contact; the connection includinga threaded bolt that extends through the central connection holes ofboth clamp members between the pins connected thereby; the connectionalso including a nut that is threaded onto the bolt thereof to securethe clamp members to each other with each pair of clamping flangesengaging the associated pin at three spaced locations of line contact;one clamp member which includes the pair of clamping flanges that eachhave one location for engaging the associated pin with line contactincluding a longitudinal groove extending between the clamping flangesthereof and having a pair of side surfaces; the bolt of the connectionhaving a head that is received within the groove and has a pair of flatsurfaces each of which is positioned by one of the side surfaces of thegroove to permit tightening of the nut for securing the clamp members toeach other; and the other clamp member being engaged by the nut andhaving the pair of clamping flanges which each have two locations forengaging the associated pin with line contact.
 5. In an endless trackfor a track laying vehicle, said endless track being of the typeincluding a plurality of shoe assemblies each of which includes a pairof laterally spaced shoes and a pair of round pins extendingtherebetween, a center connector for connecting adjacent shoe assembliesby extending between adjacent pins thereof at a location between thelaterally spaced shoes, said center connector comprising: a pair ofclamp members including two pairs of opposed clamping surfaces; oneclamping surface of each pair including one location for engaging theassociated round pin with line contact that constitutes the soleengagement thereof with the pin; the other clamping surface of each pairincluding two spaced locations for engaging the associated round pinwith two spaced line contacts that constitute the only engagementthereof with the pin; and a connection for securing the clamp members toeach other with each pair of clamping surfaces thereof engaging eachround pin at the three locations of line contact which form a triangularshape.
 6. A track center connector as in claim 5 wherein each clampmember includes a central connection hole and a pair of clamping flangesextending in opposite directions from the central connection hole, oneclamp member having the clamping flanges thereof each provided with oneof the locations for engaging the associated round pin with linecontact, and the other clamp member having the clamping flanges thereofeach provided with the other two locations for engaging the associatedpin with line contact.
 7. A track center connector as in claim 6 whereinthe connection includes a threaded bolt that extends through the centralconnection holes of both clamp members between the round pins connectedthereby, and the connection also including a nut that is threaded ontothe bolt thereof to secure the clamp members to each other with eachpair of clamping flanges engaging the associated round pin at threespaced locations of line contact.
 8. A track center connector as inclaim 7 wherein said one clamp member includes a longitudinal grooveextending between the clamping flanges thereof, and the bolt of theconnection having a head that is received within the groove and has atleast one flat surface positioned by the groove to permit tightening ofthe nut for securing the clamp members to each other.